Crane boom guard attachment



Aug. 23, 1960 A. J. THOMAS 2,950,016

CRANE BOOM GUARD ATTACHMENT Filed Jan. 24, 1958 INVENTOR wig/mm mam-7,

United States Patent CRANE BOOM GUARD ATTACHMENT Arthur J. Thomas, Little Rock, Ark., assignor, by mesne assignments, to Saf-T-Boom Corporation, a corporation of Arkansas Filed Jan. 24, 1958, Ser. No. 711,063

8 Claims. (Cl. 212-1) This invention relates generally to insulating apparatus and more specifically to a safety device or guard for crane and well drilling machines having high booms.

Despite the added caution exercised by crane operators when working adjacent high voltage electrical lines, the booms are too often accidentally moved into contact therewith resulting in death or serious injury to the operator and other persons and in a short circuit and damage to the electric line.

The chief object of the present invention is tov provide a readily attachable safety device in the form of a guard for the booms of cranes and well drilling machines which will eliminate danger and injury to the operator and other workmen such as pipe fitters, iron workers, bystanders, etc. as well as damage to electric lines from short circuits when a crane boom is accidentally or otherwise moved into contact with such lines.

Another important object of the present invention is to provide a light-weight guard for crane booms which is formed of insulated members so as to render it impossible to short circuit electric lines when in contact therewith.

A further important object of the present invention is to provide a guard for crane booms which is mounted on the boom and insulated therefrom so as to prevent the transmission of electric currents to the boom, its operator, and other adjacent persons.

A still further important object of the present invention is to provide a strong, lightweight, readily attachable guard for crane booms which is pivotally mounted so as to accommodate for the changing angle between the boom and the gantry cables and which is partially supported by and effects a minimum of wear to the gantry cables.

Another object of the present invention is to provide a guard of the type described which will be susceptible of ready and economical manufacture, and will be rugged and of long life in use.

Other objects and advantages of the present invention will become apparent during the course of the following description.

In the drawings, I have shown one embodiment of the invention. In this showing:

Figure 1 is a side elevational view of the outer end of a crane boom showing the guard comprising the present invention in operative position thereon;

Figure 2 is an upper end elevational view thereof to an enlarged scale;

Figure 3 is a lower end elevational view thereof looking along the lines 33 of Figure 1;

Figure 4 is a side elevational view of one of the inner end supports to a further enlarged scale;

Figure 5 is a fragmentary view looking on the line 55 of Figure 2 and showing the upper end mounting of the guard on a boom; and

Figure 6 is a sectional view to a further enlarged scale of one of the guard frame members taken on the line 6-6 of Figure 4.

Patented Aug. 23, 1960 thee ' crane boom guard as a whole which comprises a frame formed of a plurality of laterally spaced, longitudinally extending rods 12 connected at spaced intervals by semi-circularly extending rods 14 to thus form a hood which extends from a point above the boom B and the gantry cables C outwardly and downwardly with respect thereto (Figures l-3).

The two lowermost rods 12 may be formed of a single U-shaped rod with the base of the U forming the round guard portion 16 at the upper end of the frame. Similarly, the upper rods 12 terminate in semi-circular portions 18 at the upper end of the frame to extend it below the end of the boom and terminate at and arefixed to a semi-cylindrical extension 20 of the uppermost rod 14 which is thus circular.

The upper end of the guard frame 10 is supported on the end plate 22 of the boom B by a base plate 24 angularly disposed with respect to the plate 22 and welded thereto, and a pair of spaced insulators 26 is fixed to the base plate 24 and to a rod 28 pivotable in a collar 30 which is welded to a rod 32 spanning the rods 18.

The lower end of the guard 10 (Figures 1, 3 and 4) includes a pair of spaced insulators 34 fixed to and depending from the upper, longitudinally extending rods 12. A pulley 36 is fixed to the bottom of each of the insulators 34 and each bears and rotates on one of the gantry cables C. The pulleys 36 are preferably closed at their bottoms to prevent accidental displacement of the pulley wheels from the cables, the weight of the guard frame 10 normally preventing such displacement.

As seen in Figure 6, the exterior of the frame rods 12, 14, etc, is coated with an insulating plastic or ceramic material 40 which prevents the frame members of the guard 10 from short circuiting any power lines which it may contact. The insulators 26 and 34 are preferably standard 50,000 volt insulators of 5,000 lbs. drop test so as to be of adequate electrical resistance and mechanical strength.

It will now be apparent that the novel boom guard described comprises a very important safeguard for the booms of cranes and well drilling machines, may be readily attached and will not effect any wear or tear on the gantry lines during operation.

It is to be understood that the form of the invention herewith shown and described is to be taken as a preferred example of the same and that various changes in the shape, size and arrangement of parts may be resorted to without departure from the spirit of the invention or the scope of the sub-joined claims.

I claim:

1. A guard for preventing the boom of a crane, etc. from contacting a power line when moved thereagainst comprising an elongated frame of spaced, connected members adapted to project outwardly from the top and sides of the boom, and means for mounting said frame on the upper end of a boom with one end of the frame projecting therebeyond so as to contact a power line instead of the boom, said mounting means including insulators for electrically insulating the boom from said frame when said frame is moved against a power line.

2. A guard for preventing the boom of a crane, etc. from contacting a power line when moved thereagainst comprising an elongated frame of spaced, connected members adapted to project outwardly from the top and sides of the boom, and means for mounting said frame on the upper end of a boom with one end of the frame projecting therebeyond so as to contact a power line instead of the boom, said frame including insulating mat'erial to prevent the 'short circuiting of a power line when the boom guard i's'rnoved into contact therewith.

3. A guard for preventing the boom of a crane, etc. from contacting a power line when moved thereagainst comprising an elongated frame of spaced, connected members adapted to project outwardly from the top and sides of the boom, and means for mounting said frame on the upper end of 'a boom with one end of the frame projecting therebeyond so as to contact a power line instead of the boom, insulating material being provided on the surfaces of said frame members to prevent the short-circuiting of a power line when the boom guard is moved into contact therewith.

4. A device as recited in claim 1 wherein said frame includes insulating material to prevent the short-circuiting of a power line.

5. A guard adapted to be interposed between the boom of a crane, etc. including gantry cables and a power line comprising an elongated frame of spaced, connected, rod-like members, and means mounting said frame in spaced relation from the upper sides and top of the boom with one end of said frame extending beyond the outer end of the boom whereby engagement with a power line is had by the frame, said mounting means comprising an insulated upper pivotal connection between said frame and the boom and a pair of insulated pulleys fixed to and supporting the lower end of said frame by rotatably resting on the gantry cables.

6. In combination a boom member, a guard mounted on said boom member in spaced surrounding relation to a portion of the boom and the terminal end thereof, and electrical insulating means interposed between said guard and said boom member for preventing the transmittal of current therebetween upon accidental contact of saidguard with a current conductor.

7. The combination of claim 6 in which said guard comprises a skeletonized framework including elongated elements extending longitudinally of said boom, and a plurality of longitudinally spaced, transverse rod elements secured to said elongated elements, said framework extending beyond the terminal end of said boom member.

8. The combination of claim 7 in which said frame work is pivotally mounted on the terminal end of said boom member, gantry cables are operatively connected to said boom and extend longitudinally thereabove, and friction-reducing means depend from said framework and are mounted on said gantry cables for permitting movement of the gantry cables during vertical pivotal movement of said boom and pivotal movement of said framework at the terminal end of the boom as the boom is raised and lowered.

References Cited in the file of this patent UNITED STATES PATENTS 2,355,361 Brown Aug. 8, 1944 2,615,969 Albrecht c. Oct. 28, 1952 2,730,245 Auld Jan. 10, 1956 2,789,282 Winters Apr. 16, 1957 

